Single arterial trunk arising from the aortic arch. Evidence that the fifth branchial arch can persist as the definitive aortic arch.

A seven month old female having a single arterial trunk arising from the aortic arch is presented. The baby also had severe coarctation of the aorta and a patent ductus arteriosus. This anomaly cannot be explained by Edwards' embryonic double aortic arch model. However, it can be explained by persistence of the fifth branchial arch as the definitive aortic arch.